1. Field
The present disclosure relates generally to identifying the position of a mobile platform, such as a robot or an unmanned air vehicle, and to identifying the accuracy of the identified position of the mobile platform. More particularly, the present disclosure relates to a method and apparatus for identifying the position of a mobile platform using images obtained from a camera system on the mobile platform and position information received from other mobile platforms and devices.
2. Background
Mobile platforms may be used to perform a variety of tasks in various environments. For example, a robot is an example of an automated mobile platform. A robot may be used to perform various tasks for manufacturing a product in a factory or other environment. For example, a number of robots may be used to assemble an aircraft or another vehicle or other product.
An unmanned air vehicle is another example of an automated mobile platform. An unmanned air vehicle may be used to perform a variety of missions in various operating environments. For example, an unmanned air vehicle may be controlled to perform various tasks while performing a surveillance mission or other mission.
The position of a mobile platform in an operating environment may be defined by the location of the platform in the operating environment, the orientation of the platform in the operating environment, or both. Accurately controlling the position of a mobile platform in an operating environment is desirable so that the tasks performed by the platform may be performed effectively. Accurately identifying the position of the mobile platform in the operating environment at any point in time may be desirable so that the position of the mobile platform in the operating environment may be accurately controlled.
For example, the position of an unmanned air vehicle or other aircraft at any point in time may be defined in terms of the location of the aircraft in three-dimensional space, the orientation of the aircraft, or both the location and orientation of the aircraft. For example, the location of an aircraft may be defined by geographic coordinates and the altitude of the aircraft. The orientation of an aircraft may be defined in terms of an angle of the aircraft in relation to a given line or plane, such as the horizon. The orientation of the aircraft may be referred to as the attitude. The attitude of an aircraft may be described with reference to three degrees of freedom, referred to as roll, pitch, and yaw.
Various systems may be used to identify the position of a mobile platform. For example, the location of an unmanned air vehicle or other aircraft may be identified using a global positioning system (GPS). In this case, global positioning system hardware on the aircraft includes a receiver configured to receive signals from a number of satellites. Additional hardware and software on the aircraft identifies the current location of the aircraft from the received satellite signals.
Alternatively, a radio navigation system on the aircraft may be used to identify the current location of the aircraft from radio signals received from a number of known locations on the ground. Various hardware or hardware and software systems also may be used to identify the orientation of the aircraft. For example, an electromechanical gyroscope system may be used to identify the attitude of the aircraft at any point in time.
Accurate knowledge of the current position of an unmanned air vehicle or other aircraft in an operating environment is desirable for effectively controlling the aircraft to perform a mission. Current systems and methods for identifying the position of an aircraft may affect efficient operation of the aircraft.
Current systems and methods for identifying the position of an aircraft in an operating environment may not identify the position of the aircraft as accurately as desired in various operating environments, under various operating conditions, or in other situations. For example, global positioning systems (GPS) and radio navigation systems may not be able to identify accurately the position of an aircraft in some cases, such as when the signals used by these systems are not available or are blocked from being received by the aircraft by features in the operating environment.
Current systems and methods for identifying the positions of other mobile platforms in various operating environments also may not identify the current position of the mobile platform as accurately as desired in various operating environments, operating conditions, or other situations. For example, indoor positioning systems may not be able to identify accurately the position of the platform in some cases, such as when signals are blocked from being received by the platform. In other cases, systems on-board the platform may not be able to identify accurately the position of the platform over periods of time, such as when initial conditions are inaccurate and when errors have accumulated due to sensor drift, wheel slippage, or for other reasons.
Accordingly, it would be beneficial to have a method and apparatus that takes into account one or more of the issues discussed above, as well as possibly other issues.